/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#include "itkMath.h"
#include "itkGaussianBlurImageFunction.h"

int itkGaussianBlurImageFunctionTest(int, char* [] )
{
  constexpr unsigned int Dimension = 2;
  using PixelType = float;
  using ImageType = itk::Image< PixelType, Dimension >;
  using GFunctionType = itk::GaussianBlurImageFunction< ImageType >;

  // Create and allocate the image
  ImageType::Pointer      image = ImageType::New();
  ImageType::SizeType     size;
  ImageType::IndexType    start;
  ImageType::RegionType   region;

  size[0] = 50;
  size[1] = 50;

  start.Fill( 0 );
  region.SetIndex( start );
  region.SetSize( size );

  image->SetRegions( region );
  image->Allocate(true); // initialize buffer to zero

  // Fill the image with a straight line
  for(unsigned int i=0;i<50;i++)
  {
    ImageType::IndexType ind;
    ind[0]=i;
    ind[1]=25;
    image->SetPixel(ind,1);
    ind[1]=26;
    image->SetPixel(ind,1);
  }

  // Test the derivative of Gaussian image function
  GFunctionType::Pointer gaussianFunction = GFunctionType::New();
  gaussianFunction->SetInputImage( image );
  itk::Index<2>   index;
  index.Fill(25);

  // Testing Set/GetVariance()
  std::cout << "Testing Set/GetVariance(): ";
  gaussianFunction->SetSigma(5.0);
  const GFunctionType::SigmaArrayType & sigma = gaussianFunction->GetSigma();

  for(unsigned int i=0;i<Dimension;i++)
  {
    if( sigma[i] !=  5.0)
    {
    std::cerr << "[FAILED]" << std::endl;
    return EXIT_FAILURE;
    }
  }
  std::cout << "[PASSED] " << std::endl;

  // Testing Set/GetExtent()
  std::cout << "Testing Set/GetExtent(): ";

  gaussianFunction->SetExtent(5.0);
  const GFunctionType::ExtentArrayType & ext = gaussianFunction->GetExtent();

  for(unsigned int i=0;i<Dimension;i++)
  {
    if( ext[i] !=  5.0)
    {
    std::cerr << "[FAILED]" << std::endl;
    return EXIT_FAILURE;
    }
  }
  std::cout << "[PASSED] " << std::endl;


   // Testing Set/GetMaximumError()
  {
    std::cout << "Testing Set/GetMaximumError(): ";
    GFunctionType::ErrorArrayType  setError;

    setError.Fill( 0.05 );
    gaussianFunction->SetMaximumError( setError );

    const GFunctionType::ErrorArrayType & readError =
                            gaussianFunction->GetMaximumError();

    for(unsigned int i=0;i<Dimension;i++)
    {
      if( std::fabs( setError[i] - readError[i] ) > 1e-6 )
      {
      std::cerr << "[FAILED]" << std::endl;
      return EXIT_FAILURE;
      }
    }
    std::cout << "[PASSED] " << std::endl;
  }

  // Testing Set/GetMaximumKernelWidth()
  {
    std::cout << "Testing Set/GetMaximumKernelWidth(): ";
    int setKernelWidth = 47;

    gaussianFunction->SetMaximumKernelWidth( setKernelWidth );

    int readKernelWidth = gaussianFunction->GetMaximumKernelWidth();

    if( readKernelWidth != setKernelWidth )
      {
      std::cerr << "[FAILED]" << std::endl;
      return EXIT_FAILURE;
      }
    std::cout << "[PASSED] " << std::endl;
  }

  // Testing Set/GetUseImageSpacing()
  {
    std::cout << "Testing Set/GetUseImageSpacing(): ";
    bool useImageSpacing = true;

    gaussianFunction->SetUseImageSpacing( useImageSpacing );
    if( gaussianFunction->GetUseImageSpacing() != useImageSpacing )
      {
      std::cerr << "Set/GetUseImageSpacing() FAILED !" << std::endl;
      return EXIT_FAILURE;
      }

    useImageSpacing = false;

    gaussianFunction->SetUseImageSpacing( useImageSpacing );
    if( gaussianFunction->GetUseImageSpacing() != useImageSpacing )
      {
      std::cerr << "Set/GetUseImageSpacing() FAILED !" << std::endl;
      return EXIT_FAILURE;
      }

    gaussianFunction->UseImageSpacingOn();
    if( gaussianFunction->GetUseImageSpacing() != true )
      {
      std::cerr << "Set/GetUseImageSpacing() FAILED !" << std::endl;
      return EXIT_FAILURE;
      }

    gaussianFunction->UseImageSpacingOff();
    if( gaussianFunction->GetUseImageSpacing() != false )
      {
      std::cerr << "Set/GetUseImageSpacing() FAILED !" << std::endl;
      return EXIT_FAILURE;
      }


    gaussianFunction->UseImageSpacingOn(); // leave it ON for the next test.
    std::cout << "[PASSED] " << std::endl;
  }


  GFunctionType::OutputType  blurredvalue_index;
  blurredvalue_index = gaussianFunction->EvaluateAtIndex( index );

  GFunctionType::PointType pt;
  pt[0]=25.0;
  pt[1]=25.0;
  GFunctionType::OutputType  blurredvalue_point;
  blurredvalue_point = gaussianFunction->Evaluate( pt );


  GFunctionType::ContinuousIndexType continuousIndex;
  continuousIndex.Fill(25);
  GFunctionType::OutputType  blurredvalue_continuousIndex;
  blurredvalue_continuousIndex = gaussianFunction->EvaluateAtContinuousIndex( continuousIndex );


  std::cout << "Testing Evaluate(), EvaluateAtIndex() and EvaluateIndex: ";
  if( (std::fabs(blurredvalue_index-blurredvalue_point)>0.01)
     || itk::Math::NotAlmostEquals(blurredvalue_point, blurredvalue_continuousIndex) )
    {
    std::cerr << "[FAILED] : "
              << blurredvalue_index << " : "
              << blurredvalue_point << " : "
              << blurredvalue_continuousIndex <<  std::endl;
    return EXIT_FAILURE;
    }

  std::cout << "[PASSED] " << std::endl;

  std::cout << "Testing Evaluate() : ";

  if( std::fabs(blurredvalue_point-0.158)> 0.1)
    {
    std::cerr << "[FAILED]" << std::endl;
    return EXIT_FAILURE;
    }

  std::cout << "[PASSED] " << std::endl;

  gaussianFunction->Print( std::cout );
  std::cout << "GaussianBlurImageFunctionTest: [DONE] " << std::endl;
  return EXIT_SUCCESS;
}
